Is it better to let 18650 batts "rest" before charging?

[Darryl Licht]

OK, I am new to Lithium Ion batts and 18650's. I have a Nitecore D4 charger, and noticed that the batt I used 2 days ago charged much faster than the one I had just used.

For overall batt life, Is it better to let a batt "rest" before popping into the charger, or just charge it as soon as it is depleted to 20%?

 

[Ryedan]

IMO, leaving a battery for a couple of days at 20% or about 3.5V at rest is slightly easier on it than leaving it at 100% or about 4.2 V for a couple of days. I use a set of 4 batts for daily vaping. I cycle through them in order by using one until it goes down to 3.6 - 3.7V or about 35%, then replace it. I charge a pair when I have about half a day remaining on the last one. This way the fully charged time is between 1/2 and 1 1/2 days after charging and any batts that are waiting for charge are at 3.7'ish.

I believe leaving a battery to rest for a few hours after use is better than not doing that. Letting them rest for at least a few hours after charge is also good. I have no idea how much difference it makes.

I have a couple of times discharged down to 2.5V by mistake and then I immediately charge it at least partially. This is with hybrids like the VTC series, LG HE2 and Samsung 25R that are rated down to 2.5V. I believe that is really hard on them though and any less than 2.5V will hurt them and become a safety risk.

I have a few batteries that I don't use often. I leave them at 3.7-3.8V until I need one.

 

[twgbonehead]

If you are vaping at high power, then letting them rest for a bit is a good thing. Not sure what "20%" really means, though. What voltage are they at?

If a battery has been heavily discharged (high-power, to a low voltage) you are better off recharging it immediately (at least for a bit). It's bad for these batts to sit when they are undercharged.

If you're not using them heavily, then recharge immediately. They like being at least half-full.

 

[Rat2chat2]

Good post from Ryedan. Here is a sight that has everything you ever wanted to know about batteries. And Baditudes blogs are an excellent resource.

Basic to Advanced Battery Information from Battery University

I just got the same charger and I love it. I had a Nitecore before and it charged my batteries to 4.16 always. The new NiteCore charges my batteries to 4.20. Not sure why the difference but it is cool. It is funny but somehow I can just tell when the battery gets down to 3.7 which is when I always charge mine. I also number my batteries and use them in order. I fell like it is good to rotate them (and I'm ....)

This also allows the battery to rest so it's all good.

 

[Ryedan]

No, one of the advantages of lithium-ion batteries is that they do not need to rest. Lithium ion batteries do not have memory. They also have one of the lowest self-discharge rates. Actually it is recommended to charge immediately after they are discharged.

So in summary, don't let them rest. Charge them back up right away for best results.

So you're saying it's better to have them sit fully charged for days after every charge rather than at 3.3 - 3.7V? If this is true it goes against everything I thought I knew about not leaving them at full charge for a long time. I would like to correct that if it's true. A link to this information would be great

 

[Ryedan]

You are right about storage. It's best to store them at about 50% capacity at 3.8 volts, this is for long-term storage. If only a few days, or even weeks, li-ion may not even begin self-discharging enough to notice.

When I say recharge immediately, it is is for use go ahead and charge to it's full capacity. But if going to store it, recharge to 50% capacity instead.

Li-ion should not be kept at low voltages for too long as it has some negative effects on the internal chemistry.

No memory or cycling:

I hear you and I agree (see post #2).

On a completely different note, you are I believe what is considered by ECF a accessories supplier. It's probably in your best interest to check the rules to confirm that. If this is the case you need to register with ECF as that.

I'm not trying to give you a hard time here, just letting you know about it

ETA: Here is the ECF suppliers information page.

 

[tFOrRESTee]

Guys, I notice that if my mod shows say 40% battery left, and I let it rest for a while, then my batteries have the magical power to refill themselves say back to 43%. What gives?

 

[Ryedan]

Guys, I notice that if my mod shows say 40% battery left, and I let it rest for a while, then my batteries have the magical power to refill themselves say back to 43%. What gives?

What I think you're seeing is your battery's ability to consolidate the chemical change after electrons flow (the battery is discharged a bit). It's completely normal and all batts do this as far as I know.